EP0265634A1 - Echo sounder - Google Patents

Echo sounder Download PDF

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Publication number
EP0265634A1
EP0265634A1 EP87112775A EP87112775A EP0265634A1 EP 0265634 A1 EP0265634 A1 EP 0265634A1 EP 87112775 A EP87112775 A EP 87112775A EP 87112775 A EP87112775 A EP 87112775A EP 0265634 A1 EP0265634 A1 EP 0265634A1
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EP
European Patent Office
Prior art keywords
echo
amplifier
operational amplifier
diode
resistor
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Granted
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EP87112775A
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German (de)
French (fr)
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EP0265634B1 (en
Inventor
Manfred Gerlach
Hans-Dieter Richartz
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Fried Krupp AG
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Fried Krupp AG
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/56—Display arrangements
    • G01S7/60—Display arrangements for providing a permanent recording
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
    • G01S7/523—Details of pulse systems
    • G01S7/526—Receivers
    • G01S7/527—Extracting wanted echo signals
    • G01S7/5276—Extracting wanted echo signals using analogue techniques

Definitions

  • the invention relates to an echo sounder, in particular a surveying sounder, of the type specified in the preamble of claim 1.
  • Echosounders used as navigation or surveying plummets primarily have the task of continuously recording echoes of the boundary layer between water and sea floor, so-called ground echoes, in order to be able to determine the depth of the water from them correctly.
  • the desired complete recording is made more difficult by the fact that the received ground chos are rarely a direct image of the transmission pulse. Due to unevenness, interference forms at the water / soil boundary layer, which deforms the soil echo compared to the transmission pulse. For example, the envelope of the ground echo can show dips, the rising edge of the ground echo can be deformed, and the echo can also be lengthened compared to the transmission pulse. When the ship is moving, the echo amplitude fluctuations are considerable due to constantly changing interference structures.
  • the circuit diagram shown in FIG. 1 represents the receiving part 10 of an echo sounder.
  • the representation of the well-known transmission part with transmission pulse generator and transmission converter is omitted - since it is not relevant here.
  • the receiving part 10 has a sound converter 11 with directional characteristic for the directional reception of the echoes triggered by the transmission pulses, a non-limiting pre-or echo amplifier 12, a registration amplifier which is designed as an operational amplifier 13, and one connected to the registration amplifier 13 via a first diode 19 Registration device 14 in the form of a Registration points are only perceived as a gray haze.
  • An advantageous embodiment of the invention also results from claim 4.
  • An advantageous embodiment of the invention also results from claim 5.
  • This embodiment is advantageous when using such echo writers or thermal printers which can record in at least two gray levels or degrees of blackening.
  • the third diode transmits the natural form of the echo voltage present at the output of the envelope rectifier directly to the output of the first diode connected downstream of the registration amplifier. There, the original echo voltage becomes the 50-fold amplified echo voltage.
  • the object is achieved according to the invention in an echo sounder of the type specified in the preamble of claim 1 by the features in the characterizing part of claim 1.
  • a negative directional voltage builds up, which is increased with each positive half wave of the echo voltage.
  • the amplitudes of the echo voltages applied to the registration amplifier are each reduced by this reference voltage.
  • the recording device can thus only register those voltage values that are greater than this reference voltage. This condition is met by the first positive half-waves originating from the front echo and - relatively often - by the positive half-waves originating from the sediment echo of each echo voltage. It can also be satisfied by other positive half-waves in the echo voltages that result from interference phenomena.
  • the recording device records the latter as more or less distributed points, while the sediment echoes are registered as points that are always in the same place, ie water depth.
  • the integrability of the eye will therefore recognize the points of the sediment echoes as a continuous echo trace, especially if the points are written in deep black while the others are caused, the gain of the registration amplifier can be switched over in at least two stages in order to register the different echotypes with different intensities or to record them with different degrees of blackening.
  • the switching of the amplification takes place depending on the exceeding of a predetermined threshold by the instantaneous amplitude of the received echoes.
  • the threshold generated by the threshold circuit as the mean value of the echo amplitudes over several solder periods adapts itself automatically to the strength of the bottom echoes, so that the weaker fish echoes are reliably recognized. Echoes with smaller amplitudes, such as fish echoes, become gray and echoes with large amplitudes, such as bottom echoes, are written in black or vice versa.
  • the echo traces of sediment echoes can be represented with such echo sounders, however, because of the large fluctuation in the amplitude, the water / soil boundary layer cannot be displayed in a sharply delimited manner, since overdriving of the amplifier for reasons of sediment echo detection must not be permitted.
  • the invention has for its object to improve an echo sounder of the type mentioned in such a way that both a complete and high-contrast representation of the echo trace from the water / soil boundary layer as well as the recording of soil layers and sediment lines is possible.
  • the gain of the echo amplifier is automatically or manually increased so far in known echo sounders that the ground echo is limited in amplitude.
  • Soil layers and sediment lines can be detected by so-called sediment echoes.
  • Such sediment echoes arise from the reflection of the sound impulse penetrating into the sediment or the bottom layer at the lower boundary layer of the sediment or the bottom layer facing away from the water.
  • the amplitudes of such sediment echoes are often considerably lower than those of the bottom echo, the amplitude of which is determined by the reflection at the water / sediment boundary layer, because the damping of the sound in the sediment layer is considerably greater than the damping in the same water section.
  • the bottom echo appears longer compared to the transmission pulse and covers the sediment echo (s) of the sediment layer or layers just below the surface. If you overdrive the echo amplifier, these smaller sediment echoes are lost in the bottom echo.
  • an echo sounder preferably used as a fish solder, of the type mentioned at the outset (DE-PS 15 66 848), in which to distinguish between ground echoes and fish echoes that of schools of fish Thermal printer or thermal recorder 14.
  • the structure and function of a thermal recorder are described, for example, in DE-OS 31 12 871.
  • the sound transducer 11, the echo amplifier 12, the operational amplifier 13 and the thermal recorder 14 are all connected in series. Between the echo amplifier 12 and the operational amplifier 13, a rectifier circuit, hereinafter referred to as threshold circuit 15, is switched on, which generates a threshold adapted to the forehead echo of the ground echo received in the form of a reference voltage for the operational amplifier 13.
  • threshold circuit 15 a rectifier circuit, hereinafter referred to as threshold circuit 15, is switched on, which generates a threshold adapted to the forehead echo of the ground echo received in the form of a reference voltage for the operational amplifier 13.
  • the threshold circuit 15 has an envelope rectifier 16 connected on the input side to the output of the echo amplifier 12 and a differentiating element in the form of a capacitor 17 connecting the output of the envelope rectifier 16 to the non-inverting input of the operational amplifier 13 and a series circuit of a first resistor connected in parallel to the non-inverting input of the operational amplifier 13 18 and a second diode 20.
  • This series circuit is connected in parallel with a second resistor 21, the resistance of which is substantially greater than that of the first resistor 18.
  • the operational amplifier 13 has a 50-fold gain and is on the output side via the series connection of a third resistor 22 and the diode 19 already mentioned with the input of the thermal recorder 14 connected.
  • the output of the diode 19 is connected to zero potential via a fourth resistor 23.
  • thermal recorder 14 which can record at least in two gray levels or degrees of blackening, as described in DE-OS 31 12 871, it is advantageous to output the envelope rectifier 16 via a third diode 24 to the output of the first diode 19, that is to say directly at the input of the thermal pen 14.
  • a transmission pulse is shown schematically in FIG. 2.
  • the echoes triggered by reflection of the sound pulses on or in the sea floor are received by the sound converter 11, converted into an electrical voltage and amplified by the non-limiting echo amplifier 12.
  • An echo voltage is present at the output of the echo amplifier 12, as is schematically outlined in FIG. 3.
  • the bottom echo is extended compared to the transmission pulse, since sound energy does not only return directly from the sea floor from the vertical below the sound transducer 11, but also from the entire area of the transducer directional characteristic.
  • the bottom echo initially shows a clear echo front, which is triggered by the reflection of the sound impulse at the water / soil interface, the so-called front echo.
  • a section can then be seen in which the envelope of the ground echo is torn by interference.
  • a sediment echo is embedded in the bottom echo, which due to the greater damping in the Sediment layer has a much smaller amplitude than the forehead echo and appears later, since the sediment layer is below the surface of the sea floor, i.e. in time behind the water / soil boundary layer.
  • the echo voltage of the ground echo After passing through the envelope rectifier 16, the echo voltage of the ground echo has the course shown in FIG. 4.
  • the positive half wave a characterizes the front echo triggered at the water / soil boundary layer, the half wave e the sediment echo triggered by the lower boundary layer of a sediment layer lying below the surface, while the half waves b, c, d and f result from dips in the envelope of the ground echo from interference.
  • the echo voltage at point 4 at the output of the envelope rectifier 16 is differentiated via the capacitor 17 and the low-resistance resistor 18.
  • each of the write pulses a and e generates a continuous track, while due to the statistically fluctuating write pulses b and f or sometimes c and d an irregular dot cluster is written.
  • the first half waves a originating from the front echo are recorded without gaps.
  • the half wave e of the echo voltages fluctuates strongly in the amplitude from bottom echo to bottom echo, so that with some of the sediment echoes the half waves are not large enough to penetrate the positive voltage range and thus trigger a write pulse.
  • all these half-waves generated by the sediment echoes within the echo voltage are always at the same point in time - and thus the solder points are always printed at approximately the same solder depth - the eye's ability to integrate is sufficient, the selective blackening caused by these write pulses on the recording paper to identify as an echo track.
  • the eye is supported by the fact that all voltage crests in points 5 of the circuit are in the positive range penetrate, reinforced 50 times and thus printed by the thermal pen 14 jet black.
  • the third diode 24 is used when the thermal recorder 14 is to record the front echo and the sediment echo in the bottom echo in different shades of gray or degrees of blackening and for this purpose the writing pulses a and e generated by the front echo and the sediment echo with different intensities at the input of the Thermal pen 1 4 must be placed.
  • the echo voltages shown in FIGS. 4 and 6 are added together, so that the write pulses a and e which reach the thermal recorder 14 have different amplitudes.

Abstract

In an echo sounder with a sound transducer (11) for receiving the echo, an echo recorder (14) for recording the echo traces and a recording amplifier (13) for driving the echo recorder, a threshold circuit, which applies to the recording amplifier constructed as operational amplifier a directional voltage individually matching the respective echo, is arranged between sound transducer and recording device for the purpose of recording echo traces caused by ground layers with simultaneous gapless and high-contrast representation of the echo trace of the water/ground boundary layer. For this purpose, the threshold circuit exhibits an envelope detector (16), a differentiating section (17, 21) connecting the latter to the operational amplifier and a series circuit of a resistor (18) and a diode (20) connected in parallel with the input of the operational amplifier (13). <IMAGE>

Description

Die Erfindung betrifft ein Echolot, insbesondere ein Vermessungslot, der im Oberbegriff des Anspruchs 1 angegebenen Gattung.The invention relates to an echo sounder, in particular a surveying sounder, of the type specified in the preamble of claim 1.

Als Navigations- oder Vermessungslote verwendete Echolote haben in erster Linie die Aufgabe, Echos der Grenzschicht zwischen Wasser und Meeresboden, sog. Bodenechos, lückenlos aufzuzeichnen, um daraus einwandfrei die Wassertiefe ermitteln zu können. Die angestrebte lückenlose Aufzeichnung wird aber dadurch erschwert, daß die empfangenen Bodenchos selten ein direktes Abbild des Sendeimpulses sind. An der Grenzschicht Wasser/Boden bilden sich aufgrund von Unebenheiten Interferenzen aus, die das Bodenecho gegenüber dem Sendeimpuls verformen. So kann die Hüllkurve des Bodenechos Einbrüche zeigen, die Anstiegsflanke des Bodenechos verformt und auch das Echo gegenüber dem Sendeimpuls zeitlich verlängert sein. Beim fahrenden Schiff sind dabei wegen sich ständig ändernden Interferenzstrukturen die Echoamplitudenfluktuationen erheblich.Echosounders used as navigation or surveying plummets primarily have the task of continuously recording echoes of the boundary layer between water and sea floor, so-called ground echoes, in order to be able to determine the depth of the water from them correctly. The desired complete recording is made more difficult by the fact that the received ground chos are rarely a direct image of the transmission pulse. Due to unevenness, interference forms at the water / soil boundary layer, which deforms the soil echo compared to the transmission pulse. For example, the envelope of the ground echo can show dips, the rising edge of the ground echo can be deformed, and the echo can also be lengthened compared to the transmission pulse. When the ship is moving, the echo amplitude fluctuations are considerable due to constantly changing interference structures.

Um eine eindeutige, scharfe und kontrastreiche Echospur der Grenzschicht Wasser/Boden mittels des als des Stirnechos hinzuaddiert, so daß die Originalechospannung in jedem Fall eine steile Anstiegsflanke erhält.In order to create a clear, sharp and high contrast echo trace of the water / soil boundary layer using the as of the front echo added, so that the original echo voltage in any case receives a steep rising edge.

Die Erfindung ist anhand eines in der Zeichnung dargestellten Ausführungsbeispiels im folgenden näher beschrieben. Es zeigen:

  • Fig. 1 ein Schaltbild des Empfangsteils eines Echolots,
  • Fig. 2 eine schematische Darstellung des zeitlichen Verlaufs eines Sendeimpulses mit der Sendedauer
  • Fig. 3 bis 6 jeweils ein Diagramm des Echospannungsverlaufs in den Punkten 3, 4, 5 bzw. 6 des Schaltbilds in Fig. 1.
The invention is described below with reference to an embodiment shown in the drawing. Show it:
  • 1 is a circuit diagram of the receiving part of an echo sounder,
  • Fig. 2 is a schematic representation of the time course of a transmission pulse with the transmission duration
  • 3 to 6 each show a diagram of the echo voltage curve in points 3, 4, 5 and 6 of the circuit diagram in FIG. 1.

Das in Fig. 1 dargestellte Schaltbild repräsentiert den Empfangsteil 10 eines Echolots. Auf die Darstellung des vielfach bekannten Sendeteils mit Sendeimpulsgenerator und Sendewandler ist - da hier nicht relevant - verzichtet.The circuit diagram shown in FIG. 1 represents the receiving part 10 of an echo sounder. The representation of the well-known transmission part with transmission pulse generator and transmission converter is omitted - since it is not relevant here.

Der Empfangsteil 10 weist einen Schallwandler 11 mit Richtcharakteristik zum gerichteten Empfang der von den Sendeimpulsen ausgelösten Echos, einen nicht begrenzenden Vor- oder Echoverstärker 12, einen Registrierverstärker, der als Operationsverstärker 13 ausgebildet ist, und ein über eine erste Diode 19 an dem Registrierverstärker 13 angeschlossenes Registriergerät 14 in Form eines Registrierpunkte nur als Grauschleier wahrgenommen werden.The receiving part 10 has a sound converter 11 with directional characteristic for the directional reception of the echoes triggered by the transmission pulses, a non-limiting pre-or echo amplifier 12, a registration amplifier which is designed as an operational amplifier 13, and one connected to the registration amplifier 13 via a first diode 19 Registration device 14 in the form of a Registration points are only perceived as a gray haze.

Vorteilhafte Ausführungsformen der Erfindung mit zweckmäßigen Ausgestaltungen und Weiterbildungen ergeben sich aus den weiteren Ansprüchen.Advantageous embodiments of the invention with expedient refinements and developments result from the further claims.

Eine vorteilhafte Ausführungsform der Erfindung ergibt sich dabei aus Anspruch 3. Durch den zusätzlichen Widerstand wird eine Entladung des von Kondensator, Widerstand und Diode gebildeten Differenzierglieds bis zum Empfang des nächsten Bodenechos sichergestellt.An advantageous embodiment of the invention results from claim 3. The additional resistance ensures that the differentiating element formed by the capacitor, resistor and diode is discharged until the next ground echo is received.

Eine vorteilhafte Ausführungsform der Erfindung ergibt sich auch aus Anspruch 4. Durch diese Verstärkung werden bei Anschluß eines Echoschreibers als Registriergerät, z. B. eines Thermodruckers, die von den positiven Spannungskuppen der Echospannung ausgelösten Registrierpunkte tiefschwarz geschrieben, wodurch die Integrationsfähigkeit des Auges zur Erkennung einer durchgehenden Echospur der Sedimentechos unterstützt wird.An advantageous embodiment of the invention also results from claim 4. This amplification when connecting an echo writer as a registration device, for. B. a thermal printer, the registration points triggered by the positive voltage crests of the echo voltage are written in deep black, which supports the ability of the eye to integrate to detect a continuous echo trace of the sediment echoes.

Eine vorteilhafte Ausführungsform der Erfindung ergibt sich auch aus Anspruch 5. Diese Ausführungsform ist bei Einsatz von solchen Echoschreibern oder Thermodruckern von Vorteil, die in mindestens zwei Graustufen oder Schwärzungsgraden aufzeichnen können. Die dritte Diode überträgt die natürliche Form der am Ausgang des Hüllkurvengleichrichters anstehenden Echospannung unmittelbar an den Ausgang der dem Registrierverstärker nachgeschalteten ersten Diode. Dort wird zu dieser Originalechospannung die 50fach verstärkte Echospannung Die Aufgabe ist bei einem Echolot der im Oberbegriff des Anspruchs 1 angegebenen Gattung erfindungsgemäß durch die Merkmale im Kennze ichenteil des Anspruchs 1 gelöst.An advantageous embodiment of the invention also results from claim 5. This embodiment is advantageous when using such echo writers or thermal printers which can record in at least two gray levels or degrees of blackening. The third diode transmits the natural form of the echo voltage present at the output of the envelope rectifier directly to the output of the first diode connected downstream of the registration amplifier. There, the original echo voltage becomes the 50-fold amplified echo voltage The object is achieved according to the invention in an echo sounder of the type specified in the preamble of claim 1 by the features in the characterizing part of claim 1.

Bei dem erfindungsgemäßen Echolot baut sich aufgrund der großen Amplituden der Echostirn der Bodenechos, im folgenden Stirnechos genannt, jeweils eine negative Richtspannung auf, die mit jeder positiven Halbwelle der Echospannung vergrößert wird. Die Amplituden der an dem Registrierverstärker anliegenden Echospannungen werden jeweils um diese Richtspannung reduziert. Von dem Registriergerät können damit nur solche Spannungswerte registriert werden, die größer als diese Richtspannung sind. Diese Bedingung wird von den vom Stirnecho herrührenden ersten positiven Halbwellen und - relativ häufig - von den vom Sedimentecho herrührenden positiven Halbwellen einer jeden Echospannung erfüllt. Sie kann auch erfüllt werden von anderen positiven Halbwellen in den Echospannungen, die von Interferenzerscheinungen herrühren. Während jedoch die von den Sedimentechos herrührenden positiven Halbwellen innerhalb der Echospannungen der Bodenechos zeitlich immer an der gleichen Stelle liegen, werden die von Interferenzen herrührenden positiven Halbwellen in den Echospannungen der einzelnen Bodenechos in ihrem zeitlichen Auftreten statistisch stark schwanken. Dadurch zeichnet das Registriergerät letztere als mehr oder weniger verteilte Punkte auf, während die Sedimentechos als immer an der gleichen Stelle, d. h. Wassertiefe, liegende Punkte registriert werden. Die Integrierfähigkeit des Auges wird daher die Punkte der Sedimentechos als durchgehende Echospur erkennen, insbesondere dann, wenn die Punkte tiefschwarz geschrieben werden, während die anderen hervorgerufen werden, die Verstärkung des Registrierverstärkers in mindestens zwei Stufen umgeschaltet werden kann, um so die verschiedenen Echotypen mit unterschiedlicher Intensität zu registrieren bzw. mit unterschiedlichem Schwärzungsgrad aufzuzeichnen. Die Umschaltung der Verstärkung erfolgt in Abhängigkeit von dem Überschreiten einer vorgegebenen Schwelle durch die Momentanamplitude der empfangenen Echos. Die von der Schwellenschaltung als Mittelwert der Echoamplituden über mehrere Lotperioden generierte Schwelle paßt sich dabei selbsttätig an die Stärke der Bodenechos an, so daß die schwächeren Fischechos zuverlässig erkannt werden. Echos mit kleineren Amplituden, wie Fischechos, werden dabei grau und Echos mit großen Amplituden, wie Bodenechos, werden schwarz oder umgekehrt geschrieben.In the echo sounder according to the invention, due to the large amplitudes of the echo front of the ground echoes, hereinafter referred to as front echoes, a negative directional voltage builds up, which is increased with each positive half wave of the echo voltage. The amplitudes of the echo voltages applied to the registration amplifier are each reduced by this reference voltage. The recording device can thus only register those voltage values that are greater than this reference voltage. This condition is met by the first positive half-waves originating from the front echo and - relatively often - by the positive half-waves originating from the sediment echo of each echo voltage. It can also be satisfied by other positive half-waves in the echo voltages that result from interference phenomena. However, while the positive half-waves originating from the sediment echoes within the echo voltages of the ground echoes are always at the same point in time, the occurrence of positive half-waves in the echo voltages of the individual ground echoes will fluctuate significantly in terms of their timing. As a result, the recording device records the latter as more or less distributed points, while the sediment echoes are registered as points that are always in the same place, ie water depth. The integrability of the eye will therefore recognize the points of the sediment echoes as a continuous echo trace, especially if the points are written in deep black while the others are caused, the gain of the registration amplifier can be switched over in at least two stages in order to register the different echotypes with different intensities or to record them with different degrees of blackening. The switching of the amplification takes place depending on the exceeding of a predetermined threshold by the instantaneous amplitude of the received echoes. The threshold generated by the threshold circuit as the mean value of the echo amplitudes over several solder periods adapts itself automatically to the strength of the bottom echoes, so that the weaker fish echoes are reliably recognized. Echoes with smaller amplitudes, such as fish echoes, become gray and echoes with large amplitudes, such as bottom echoes, are written in black or vice versa.

Mit solchen Echoloten lassen sich zwar die Echospuren von Sedimentechos darstellen, jedoch kann wegen der großen Amplitudenfluktuation die Grenzschicht Wasser/Boden nicht scharf begrenzt dargestellt werden, da eine Übersteuerung des Verstärkers aus Gründen der Sedimentechoerkennung nicht zugelassen werden darf.The echo traces of sediment echoes can be represented with such echo sounders, however, because of the large fluctuation in the amplitude, the water / soil boundary layer cannot be displayed in a sharply delimited manner, since overdriving of the amplifier for reasons of sediment echo detection must not be permitted.

Der Erfindung liegt die Aufgabe zugrunde, ein Echolot der eingangs genannten Art derart zu verbessern, daß sowohl eine lückenlose und kontrastreiche Darstellung der Echospur von der Grenzschicht Wasser/Boden als auch die Aufzeichnung von Bodenschichtungen und Sedimentlinien möglich ist.The invention has for its object to improve an echo sounder of the type mentioned in such a way that both a complete and high-contrast representation of the echo trace from the water / soil boundary layer as well as the recording of soil layers and sediment lines is possible.

Echoschreiber ausgebildeten Registriergerätes aufzeichnen zu können, wird bei bekannten Echoloten die Verstärkung des Echoverstärkers automatisch oder manuell so weit erhöht, daß das Bodenecho amplitudenmäßig begrenzt wird.To be able to record echo recorders designed recording device, the gain of the echo amplifier is automatically or manually increased so far in known echo sounders that the ground echo is limited in amplitude.

Mit solchen Echoloten ist die Aufzeichnung von Bodenschichtungen und Sedimentlinien nicht möglich. Bodenschichtungen und Sedimentlinien können durch sog. Sedimentechos detektiert werden. Solche Sedimentechos entstehen durch Reflexion des in das Sediment oder die Bodenschicht eindringenden Schallimpulses an der vom Wasser abgekehrten unteren Grenzschicht des Sediments oder der Bodenschicht. Die Amplituden solcher Sedimentechos sind oft erheblich geringer als die des Bodenechos, dessen Amplitude von der Reflexion an der Grenzschicht Wasser/Sediment bestimmt wird, weil die Dämpfung des Schalls in der Sedimentschicht erheblich größer ist als die Dämpfung in einer gleichen Wasserstrecke. Da am Meeresboden reflektierte Schallenergie nicht nur unmittelbar aus der Senkrechten unterhalb des Echolots zurückkommt, sondern aus dem gesamten Bereich der Richtcharakteristik des Echolots, erscheint das Bodenecho gegenüber dem Sendeimpuls verlängert und überdeckt das oder die Sedimentechos der kurz unter der Bodenoberfläche liegenden Sedimentschicht oder Sedimentschichten. Übersteuert man den Echoverstärker, so gehen diese kleineren Sedimentechos im Bodenecho verloren.It is not possible to record soil stratification and sediment lines with such echosounders. Soil layers and sediment lines can be detected by so-called sediment echoes. Such sediment echoes arise from the reflection of the sound impulse penetrating into the sediment or the bottom layer at the lower boundary layer of the sediment or the bottom layer facing away from the water. The amplitudes of such sediment echoes are often considerably lower than those of the bottom echo, the amplitude of which is determined by the reflection at the water / sediment boundary layer, because the damping of the sound in the sediment layer is considerably greater than the damping in the same water section. Since sound energy reflected on the sea floor does not only come directly from the vertical below the echo sounder, but from the entire range of the directional characteristic of the echo sounder, the bottom echo appears longer compared to the transmission pulse and covers the sediment echo (s) of the sediment layer or layers just below the surface. If you overdrive the echo amplifier, these smaller sediment echoes are lost in the bottom echo.

Es ist weiterhin ein vorzugsweise als Fischlot verwendetes Echolot der eingangs genannten Art bekannt (DE-PS 15 66 848), bei welchem zur Unterscheidung von Bodenechos und Fischechos, die von Fischschwärmen Thermodruckers oder Thermoschreibers 14 auf. Aufbau und Funktion eines Thermoschreibers sind beispielsweise in der DE-OS 31 12 871 beschrieben.There is also known an echo sounder, preferably used as a fish solder, of the type mentioned at the outset (DE-PS 15 66 848), in which to distinguish between ground echoes and fish echoes that of schools of fish Thermal printer or thermal recorder 14. The structure and function of a thermal recorder are described, for example, in DE-OS 31 12 871.

Der Schallwandler 11, der Echoverstärker 12, der Operationsverstärker 13 und der Thermoschreiber 14 sind alle in Reihe geschaltet. Zwischen dem Echoverstärker 12 und dem Operationsverstärker 13 ist eine Gleichrichterschaltung, im folgenden Schwellenschaltung 15 genannt, eingeschaltet, die eine an das Stirnecho des jeweils empfangenen Bodenechos angepaßte Schwelle in Form einer Richtspannung für den Operationsverstärker 13 generiert.The sound transducer 11, the echo amplifier 12, the operational amplifier 13 and the thermal recorder 14 are all connected in series. Between the echo amplifier 12 and the operational amplifier 13, a rectifier circuit, hereinafter referred to as threshold circuit 15, is switched on, which generates a threshold adapted to the forehead echo of the ground echo received in the form of a reference voltage for the operational amplifier 13.

Die Schwellenschaltung 15 weist einen eingangsseitig an dem Ausgang des Echoverstärkers 12 angeschlossenen Hüllkurvengleichrichter 16 und ein den Ausgang des Hüllkurvengleichrichters 16 mit dem nichtinvertierenden Eingang des Operationsverstärkers 13 verbindendes Differenzierglied in Form eines Kondensators 17 und einer dem nichtinvertierenden Eingang des Operationsverstärkers 13 parallelgeschalteten Reihenschaltung aus einem ersten Widerstand 18 und einer zweiten Diode 20 auf. Dieser Reihenschaltung ist ein zweiter Widerstand 21 parallelgeschaltet, dessen Widerstandswert wesentlich größer ist als der des ersten Widerstandes 18. Der Operationsverstärker 13 weist eine 50fache Verstärkung auf und ist ausgangsseitig über die Reihenschaltung eines dritten Widerstandes 22 und der bereits erwähnten Diode 19 mit dem Eingang des Thermoschreibers 14 verbunden. Der Ausgang der Diode 19 ist über einen vierten Widerstand 23 an Nullpotential gelegt.The threshold circuit 15 has an envelope rectifier 16 connected on the input side to the output of the echo amplifier 12 and a differentiating element in the form of a capacitor 17 connecting the output of the envelope rectifier 16 to the non-inverting input of the operational amplifier 13 and a series circuit of a first resistor connected in parallel to the non-inverting input of the operational amplifier 13 18 and a second diode 20. This series circuit is connected in parallel with a second resistor 21, the resistance of which is substantially greater than that of the first resistor 18. The operational amplifier 13 has a 50-fold gain and is on the output side via the series connection of a third resistor 22 and the diode 19 already mentioned with the input of the thermal recorder 14 connected. The output of the diode 19 is connected to zero potential via a fourth resistor 23.

Bei Verwendung eines Thermoschreibers 14, der mindestens in zwei Graustufen oder Schwärzungsgraden aufzeichnen kann, wie dies in der DE-OS 31 12 871 beschrieben ist, ist es von Vorteil, den Ausgang des Hüllkurvengleichrichters 16 über eine dritte Diode 24 an den Ausgang der ersten Diode 19, also unmittelbar an den Eingang des Thermoschreibers 14, zu legen.When using a thermal recorder 14, which can record at least in two gray levels or degrees of blackening, as described in DE-OS 31 12 871, it is advantageous to output the envelope rectifier 16 via a third diode 24 to the output of the first diode 19, that is to say directly at the input of the thermal pen 14.

Die Wirkungsweise des vorstehend beschriebenen Echolots ist wie folgt.The operation of the sounder described above is as follows.

Mittels des nicht dargestellten Sendewandlers werden Schallimpulse mit der Sendedauer τ senkrecht nach unten zum Meeresboden hin ausgesendet. Ein Sendeimpuls ist in Fig. 2 schematisch dargestellt. Die durch Reflexion der Schallimpulse am oder im Meeresboden ausgelösten Echos werden von dem Schallwandler 11 empfangen, in eine elektrische Spannung umgewandelt und von dem nicht begrenzenden Echoverstärker 12 verstärkt. Am Ausgang des Echoverstärkers 12 liegt eine Echospannung an, wie sie in Fig. 3 schematisch skizziert ist. Wie schon eingangs erwähnt, ist das Bodenecho gegenüber dem Sendeimpuls verlängert, da Schallenergie nicht nur unmittelbar vom Meeresboden aus der Senkrechten unterhalb des Schallwandlers 11 zurückkommt, sondern aus dem gesamten Bereich der Wandlerrichtcharakteristik. Das Bodenecho zeigt am Anfang eine deutliche Echostirn, die von der Reflexion des Schallimpulses an der Grenzschicht Wasser/Boden ausgelöst wird, das sog. Stirnecho. Danach ist ein Abschnitt zu erkennen, in welchem die Hüllkurve des Bodenechos durch Interferenzen zerrissen ist. Schließlich ist in dem Bodenecho noch ein Sedimentecho eingebettet, das wegen der größeren Dämpfung in der Sedimentschicht eine wesentlich kleinere Amplitude als das Stirnecho aufweist und zeitlich später erscheint, da die Sedimentschicht unter der Oberfläche des Meeresbodens, also zeitlich gesehen hinter der Grenzschicht Wasser/Bo den liegt.By means of the transmitter converter, not shown, sound pulses with the transmission duration τ are transmitted vertically downwards towards the sea floor. A transmission pulse is shown schematically in FIG. 2. The echoes triggered by reflection of the sound pulses on or in the sea floor are received by the sound converter 11, converted into an electrical voltage and amplified by the non-limiting echo amplifier 12. An echo voltage is present at the output of the echo amplifier 12, as is schematically outlined in FIG. 3. As already mentioned at the beginning, the bottom echo is extended compared to the transmission pulse, since sound energy does not only return directly from the sea floor from the vertical below the sound transducer 11, but also from the entire area of the transducer directional characteristic. The bottom echo initially shows a clear echo front, which is triggered by the reflection of the sound impulse at the water / soil interface, the so-called front echo. A section can then be seen in which the envelope of the ground echo is torn by interference. Finally, a sediment echo is embedded in the bottom echo, which due to the greater damping in the Sediment layer has a much smaller amplitude than the forehead echo and appears later, since the sediment layer is below the surface of the sea floor, i.e. in time behind the water / soil boundary layer.

Nach Durchlaufen des Hüllkurvengleichrichters 16 weist die Echospannung des Bodenechos den in Fig. 4 dargestellten Verlauf auf. Die positive Halbwelle a kennzeichnet das an der Grenzschicht Wasser/Boden ausgelöste Stirnecho, die Halbwelle e das von der unteren Grenzschicht einer unter der Bodenoberfläche liegenden Sedimentschicht ausgelöste Sedimentecho, während die Halbwellen b, c, d und f von Einbrüchen in der Hüllkurve des Bodenechos infolge von Interferenzerscheinungen herrühren. Die am Ausgang des Hüllkurvengleichrichters 16 im Punkte 4 liegende Echospannung wird über den Kondensator 17 und den niederohmigen Widerstand 18 differenziert. Da in Reihe mit dem Widerstand 18 die Diode 20 liegt, baut sich am Punkte 5, also am nichtinvertierenden Eingang des Operationsverstärkers 13, eine negative Richtspannung auf, sobald die positive Halbwelle a der Echospannung den Kondesator 17 passiert hat. Die Richtspannung baut sich mit einer Zeitkonstanten ab, die von der Kapazität des Kondensators 17 und dem Widerstandswert des Widerstandes 21 bestimmt ist. Jede der Halbwelle a folgende, genügend große positive Halbwelle der Echospannung vergrößert jedoch die negative Richtspannung im Punkte 5. Am nichtinvertierenden Eingang des Operationsverstärkers 13 ergibt sich ein Spannungsverlauf, wie er in Fig. 5 schematisch skizziert ist. Nur die Kuppen der größeren Halbwellen ragen in den Bereich positiver Spannungen und vermögen damit ein Ausgangssignal im Operationsverstärker 13 zu erzeugen, das die erste Diode 19 passieren kann. Die Signalspannung am Ausgang der Diode 19 - im Punkte 6 - ist in Fig. 6 schematisch dargestellt. Die von den positiven Halbwellen a, b, e und f ausgelösten Schreibimpulse gelangen an den Thermoschreiber 14 und erzeugen hier jeweils einen Lotpunkt. Da bei angenommener, konstanter Wassertiefe und Sedimentschichttiefe die Kuppen der Halbwellen a und e zeitlich immer an derselben Stelle liegen, die durch Interferenzstrukturen bedingten Kuppen der Halbwellen b, c, d und f jedoch zeitlich gesehen in ihrer Lage, Größe und Häufigkeit stark schwanken, wird im Thermodrucker 14 von den Schreibimpulsen a und e jeweils eine durchgehende Spur, erzeugt, während aufgrund der statistisch in ihrer Lage schwankenden Schreibimpulse b und f oder mitunter auch c und d ein unregelmäßiger Punkthaufen geschrieben wird. Die ersten von dem Stirnecho herrührenden Halbwellen a werden lückenlos registriert. Die Halbwelle e der Echospannungen schwankt in der Amplitude von Bodenecho zu Bodenecho stark, so daß bei einigen der Sedimentechos die Halbwellen nicht groß genug sind, in den positiven Spannungsbereich vorzudringen und damit einen Schreibimpuls auszulösen. Da jedoch alle diese von den Sedimentechos erzeugten Halbwellen innerhalb der Echospannung zeitlich immer an der gleichen Stelle liegen - und damit die Lotpunkte immer in etwa gleicher Lottiefe ausgedruckt werden - reicht die Integrierfähigkeit des Auges aus, die durch diese Schreibimpulse auf dem Registrierpapier hervorgerufene, punktuelle Schwärzung als Echospur zu identifizieren. Das Auge wird dabei dadurch unterstützt, daß alle Spannungskuppen, die im Punkte 5 der Schaltung in den positiven Bereich vordringen, 50fach verstärkt und damit von dem Thermoschreiber 14 tiefschwarz gedruckt werden. Diese tiefschwarzen Punkte, die entsprechend der Tiefe der Sedimentschicht sich auf dem Ausdruck des Thermoschreibers 14 längs einer Linie ansammeln, erkennt das Auge als deutliche Echospur, während die zwar auch tiefschwarz, jedoch in ihrer Lage statistisch verteilten Punkte, die von den Halbwellen b, c, d und f hervorgerufen werden, nur als Grauschleier wahrgenommen werden.After passing through the envelope rectifier 16, the echo voltage of the ground echo has the course shown in FIG. 4. The positive half wave a characterizes the front echo triggered at the water / soil boundary layer, the half wave e the sediment echo triggered by the lower boundary layer of a sediment layer lying below the surface, while the half waves b, c, d and f result from dips in the envelope of the ground echo from interference. The echo voltage at point 4 at the output of the envelope rectifier 16 is differentiated via the capacitor 17 and the low-resistance resistor 18. Since the diode 20 is in series with the resistor 18, a negative directional voltage builds up at the point 5, that is to say at the non-inverting input of the operational amplifier 13, as soon as the positive half-wave a of the echo voltage has passed the capacitor 17. The directional voltage decreases with a time constant which is determined by the capacitance of the capacitor 17 and the resistance value of the resistor 21. However, each positive half-wave of the echo voltage that follows the half-wave a increases the negative directional voltage at point 5. At the non-inverting input of the operational amplifier 13 there is a voltage curve as schematically outlined in FIG. 5. Only the tops of the larger half-waves protrude into the range of positive tensions and are therefore able to To generate output signal in the operational amplifier 13, which can pass through the first diode 19. The signal voltage at the output of the diode 19 - at point 6 - is shown schematically in FIG. 6. The write pulses triggered by the positive half-waves a, b, e and f reach the thermal recorder 14 and each produce a plumb point here. Since, given an assumed constant water depth and sediment layer depth, the crests of the half-waves a and e always lie at the same point in time, but the crests of the half-waves b, c, d and f caused by interference structures will fluctuate greatly in terms of their position, size and frequency over time in the thermal printer 14 each of the write pulses a and e generates a continuous track, while due to the statistically fluctuating write pulses b and f or sometimes c and d an irregular dot cluster is written. The first half waves a originating from the front echo are recorded without gaps. The half wave e of the echo voltages fluctuates strongly in the amplitude from bottom echo to bottom echo, so that with some of the sediment echoes the half waves are not large enough to penetrate the positive voltage range and thus trigger a write pulse. However, since all these half-waves generated by the sediment echoes within the echo voltage are always at the same point in time - and thus the solder points are always printed at approximately the same solder depth - the eye's ability to integrate is sufficient, the selective blackening caused by these write pulses on the recording paper to identify as an echo track. The eye is supported by the fact that all voltage crests in points 5 of the circuit are in the positive range penetrate, reinforced 50 times and thus printed by the thermal pen 14 jet black. These deep black points, which accumulate along a line on the printout of the thermal pen 14 in accordance with the depth of the sediment layer, are recognized by the eye as a clear echo trace, while the deep black, but statistically distributed points in terms of their position, are separated by the half waves b, c , d and f are only perceived as a gray haze.

Die dritte Diode 24 kommt dann zum Einsatz, wenn der Thermoschreiber 14 das Stirnecho und das Sedimentecho im Bodenecho in unterschiedlichen Graustufen oder Schwärzungsgraden aufzeichnen soll und hierzu die von dem Stirnecho und von dem Sedimentecho generierten Schreibimpulse a bzw. e mit unterschiedlicher Intensität an den Eingang des Thermoschreibers 1 4 gelegt werden müssen. Im Punkte 6 erfolgt dabei eine Addition der in Fig. 4 und 6 dargestellten Echospannungen, so daß die an den Thermoschreiber 14 gelangenden Schreibimpulse a bzw. e unterschiedliche Amplituden aufweisen. The third diode 24 is used when the thermal recorder 14 is to record the front echo and the sediment echo in the bottom echo in different shades of gray or degrees of blackening and for this purpose the writing pulses a and e generated by the front echo and the sediment echo with different intensities at the input of the Thermal pen 1 4 must be placed. At point 6, the echo voltages shown in FIGS. 4 and 6 are added together, so that the write pulses a and e which reach the thermal recorder 14 have different amplitudes.

Claims (5)

1. Echolot, insbesondere Vermessungslot, mit einem Empfangsteil zum Empfangen von durch Beschallung am Gewässergrund hervorgerufenen Bodenechos und Aufzeichnen mindestens einer Echospur, der einen Schallwandler, einen Echoverstärker, einen Registrierverstärker, ein von dem Registrierverstärker angesteuertes Registriergerät, vorzugsweise einen Echoschreiber, und eine Schwellenschaltung zum Generieren einer sich an die Stärke des Bodenechos selbsttätig anpassenden Schwelle für den Registrierverstärker umfaßt, dadurch gekennzeichnet, daß Schallwandler (11), Echoverstärker (12) und Schwellenschaltung (15) in Reihe geschaltet und an dem Eingang des als Operationsverstärker (13) ausgebildeten Registrierverstärkers angeschlossen sind, dessen Ausgang über eine erste Diode (19) mit dem Registriergerät (14) verbunden ist, und daß die Schwellenschaltung (15) einen Hüllkurvengleichrichter (16) und ein den Ausgang des Hüllkurvengleichrichters (16) mit dem Eingang des Operationsverstärkers (13) verbindendes Differenzierglied aus einem Kondensator (17) und einer dem Eingang des Operationsverstärkers (13) parallelgeschalteten Reihenschaltung von Widerstand (18) und zweiter Diode (20) aufweist.1. Echo sounder, in particular a surveying sounder, with a receiving part for receiving ground echoes caused by sonication on the bottom of the body of water and recording at least one echo track, which contains a sound transducer, an echo amplifier, a registration amplifier, a registration device controlled by the registration amplifier, preferably an echo recorder, and a threshold circuit for Generating a threshold for the registration amplifier which automatically adapts to the strength of the ground echo, characterized in that sound transducers (11), echo amplifier (12) and threshold circuit (15) are connected in series and connected to the input of the registration amplifier designed as an operational amplifier (13) are, the output of which is connected to the recording device (14) via a first diode (19), and that the threshold circuit (15) connects an envelope rectifier (16) and an output of the envelope rectifier (16) to the input of the operational amplifier (13) having a differentiating element comprising a capacitor (17) and a series circuit of resistor (18) and second diode (20) connected in parallel to the input of the operational amplifier (13). 2. Echolot nach Anspruch 1, dadurch gekennzeichnet, daß der Eingang des Operationsverstärkers (13) der nichtinvertierende Eingang des Operationsverstärkers (13) ist.2. Echo sounder according to claim 1, characterized in that the input of the operational amplifier (13) is the non-inverting input of the operational amplifier (13). 3. Echolot nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß der Reihenschaltung aus Widerstand (18) und zweiter Diode (20) ein zweiter Widerstand (21) mit gegenüber dem ersten Widerstand (18) größerem Ohmwert parallelgeschaltet ist.3. Echo sounder according to claim 1 or 2, characterized in that the series circuit comprising a resistor (18) and a second diode (20) is connected in parallel with a second resistor (21) with a larger ohmic value than the first resistor (18). 4. Echolot nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Operationsverstärker (13) eine etwa 50fache Verstärkung aufweist.4. Echo sounder according to one of claims 1 to 3, characterized in that the operational amplifier (13) has an approximately 50-fold gain. 5. Echolot nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß der Ausgang des Hüllkurvengleichrichters (16) über eine dritte Diode (24) mit dem Ausgang der ersten Diode (19) verbunden und der Verbindungspunkt über einen dritten Widerstand (23) an Nullpotential gelegt ist.5. Echo sounder according to one of claims 1 to 4, characterized in that the output of the envelope rectifier (16) via a third diode (24) connected to the output of the first diode (19) and the connection point via a third resistor (23) Zero potential is set.
EP87112775A 1986-10-01 1987-09-02 Echo sounder Expired - Lifetime EP0265634B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3633420 1986-10-01
DE19863633420 DE3633420A1 (en) 1986-10-01 1986-10-01 ECHO SOUNDER

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EP0265634A1 true EP0265634A1 (en) 1988-05-04
EP0265634B1 EP0265634B1 (en) 1991-12-11

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EP (1) EP0265634B1 (en)
JP (1) JPS6391586A (en)
DE (2) DE3633420A1 (en)
DK (1) DK514187A (en)
NO (1) NO172085C (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002048737A1 (en) * 2000-12-14 2002-06-20 Pepperl + Fuchs Gmbh Adaptive comparator circuit and acoustic distance sensor comprising said circuit
EP1067053B2 (en) † 1999-05-07 2009-03-11 Leuze electronic GmbH + Co. Device for detecting an object

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1516629B2 (en) * 1965-11-29 1970-10-29 Electroacustic Gmbh, 2300 Kiel Method and device for recording two closely spaced submarine hall signals on current-sensitive paper
DE1566848B2 (en) * 1967-08-12 1974-12-05 Fried. Krupp Gmbh, 4300 Essen Switching arrangement for echo sounders
US4052692A (en) * 1975-11-24 1977-10-04 Freeman Arthur W Accentuator circuit for underwater acoustical devices
DE3133079A1 (en) * 1981-08-21 1983-03-10 Honeywell-Elac-Nautik Gmbh, 2300 Kiel Circuit arrangement for the improved reproduction of a close succession of echoes in an echo sounder

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1516629B2 (en) * 1965-11-29 1970-10-29 Electroacustic Gmbh, 2300 Kiel Method and device for recording two closely spaced submarine hall signals on current-sensitive paper
DE1566848B2 (en) * 1967-08-12 1974-12-05 Fried. Krupp Gmbh, 4300 Essen Switching arrangement for echo sounders
US4052692A (en) * 1975-11-24 1977-10-04 Freeman Arthur W Accentuator circuit for underwater acoustical devices
DE3133079A1 (en) * 1981-08-21 1983-03-10 Honeywell-Elac-Nautik Gmbh, 2300 Kiel Circuit arrangement for the improved reproduction of a close succession of echoes in an echo sounder

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1067053B2 (en) † 1999-05-07 2009-03-11 Leuze electronic GmbH + Co. Device for detecting an object
WO2002048737A1 (en) * 2000-12-14 2002-06-20 Pepperl + Fuchs Gmbh Adaptive comparator circuit and acoustic distance sensor comprising said circuit
US7327635B2 (en) 2000-12-14 2008-02-05 Pepperl + Fuchs Gmbh Adaptive comparator circuit and acoustic distance sensor comprising said circuit

Also Published As

Publication number Publication date
EP0265634B1 (en) 1991-12-11
NO172085C (en) 1993-06-02
NO172085B (en) 1993-02-22
JPS6391586A (en) 1988-04-22
DE3633420A1 (en) 1988-04-07
DE3775168D1 (en) 1992-01-23
DK514187D0 (en) 1987-09-30
DK514187A (en) 1988-04-02
NO873897L (en) 1988-04-05
NO873897D0 (en) 1987-09-17

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